An elongated mat of plastic material is a well known product for use in homes and certain commercial applications as a protective overlay for carpeting. Generally such mats are used in association with chairs to not only protect the carpet against concentrated wear associated with movement of the chair, but also to facilitate ease of movement of the chair across the floor surface inasmuch as the chair is permitted to move across the mat as opposed to the carpet.
These mats are commonly used in commercial application in conjuction with office services. Due to the length of the desks with which such mats are used, the mats often are required to be of a length which makes storage, shipping, and retail display in their fully elongated configuration impractical, difficult and costly. Over the years attempts have been made at improving such floor mats, with the purpose of eliminating their impracticability as the primary focus. That is, efforts have been made to develop plastic products that possess easy, durable and repeatable folding characteristics which can be made by simple and economical processes. These prior efforts, however, have failed to achieve this goal so that there remains a longfelt need in the market for such a product and an economical and simple method for making the same.
Examples of such prior attempts include the device depicted in U.S. Pat. Nos. 4,448,625 and 4,476,174. These patents disclose a method of making a composite plastic product having an integrally laminated plastic strip extending transversely across the under surface of the mat and a slit extending through its upper surface downwardly to the plastic strip which facilitates folding of the mat. Such a solution, however, is undesirable because the slit extending through the upper surface of the mat can be construed by the user to be a defect, is unsightly, serves as a collection source for dirt and other minuscule particles thereby accentuating the unsightly nature thereof, and results in eventual failure of the mat. For example, since the slit is in the upper surface of the mat, the movement of the rollers of a chair over the slit causes repeated flexing of the joining plastic strip which will ultimately crack or otherwise fail. Moreover, the user is likely to be aware of the slit as his chair moves thereover.
Another example of a prior attempt is the foldable plastic product depicted in U.S. Pat. No. 4,784,888. The product of that patent, preferably a chair mat, includes an elongate hinge extending in at least one of the length and/or width directions of the product between the product's sides. The hinge is created by the formation of an angled or curved slit configuration from the underside of the plastic product which is preferably in an L-shaped configuration. This solution is also undesirable because the L-shaped slit often leads to irregularities in the upper mat surface after repeated folding. Moreover, as with the mat of the other prior art, repeated movement of the chair rollers over the slit causes repeated flexing about the slit and ultimate cracking or other failure at the slit.
In an effort to eliminate these problems, attempts have been made to produce a mat having a middle section made of a thinner material or of a more flexible material than the remaining portion of the mat. However, as yet, such mats have not been able to be produced to exhibit a uniformly hard surface, that is, one which does not yield to the forces placed upon the upper surface of the mat in the course of its normal use in the portion of the mat containing this different material. The most common problem experienced in the mats of this type is that the portion of the mat containing the different material yields and thereby results in the mat having a dip or uneven surface in that portion when a chair is rolled thereacross. Thereafter, such mats are unsuitable for their normal and intended use, that is, enabling a chair to roll across the upper surface without encountering changes in elevation. Moreover, the middle section of the more flexible softer material often will collect dirt rendering the mat unsightly.